The present invention relates to a fuel injection device for internal combustion engines.
More particularly, it relates to a fuel injection device which has a high pressure pump drawing fuel via a suction valve into a pump working space and delivering via a delivery valve the pressurized fuel into a high pressure reservoir, with a pressure control device which maintains the pressure to a definite value and a distributor driven synchronously with the engine and successively driving injection lines which lead to injection valves, and a first electrically controlled valve in a fuel line leading to the high pressure reservoir.
Such a fuel injection device is known from the U.S. Pat. No. 4,964,389 and the corresponding DE-A-38 43 467, in which a specified amount of fuel is metered via the electrically controlled valve in the fuel line leading away from the reservoir into an intermediate reservoir, the outlet of which can be linked with the distributor aperture via a second electrically controlled valve. The amount of fuel fed via the first electrically controlled valve to the intermediate reservoir which is pressurised by the injection pressure made available by the high-pressure reservoir is measured by the stroke of a reservoir piston which limits the intermediate reservoir, and the opening period of the first electrically controlled valve is correspondingly determined by a control device. The first electrically controlled valve thus controls the amount of fuel injected. The second electrically controlled valve is opened at the desired instant for injection, and the fuel stored by the intermediate reservoir is supplied to the relevant injection nozzle.
In this procedure, the second electrically controlled valve determines the injection timing. This device is rather elaborate in that it requires a high-pressure intermediate reservoir in addition to two electrically controlled valves.